ELECTROMECHANICAL FORCES AND TORQUE IN BRUSHLESS PERMANENT-MAGNET MACHINES

The calculation of electromechanical forces that are present in a machine due to the magnetic field set up by current-carrying conductors and coils, especially when in the presence of permeable iron, is one of the most important and difficult problems in the vast field of the theory and design of electrical machines. It is a problem, moreover, which is usually dealt with by empirical methods based upon test results or by the use of numerical techniques such as Finite Element Analysis. The purpose of this paper is to develop analytical formulas to evaluate the electromechanical forces and torques involved in brushless surface-mounted permanent magnet machines from design parameters. The model thus developed will then be tested by means of a numerical method (FEA).